Electronic devices, such as smart phones, tablet computers, digital media players, and so forth, increasingly employ light sensors to control the manipulation of a variety of functions provided by the device. For example, light sensors are commonly used by electronic devices to detect ambient lighting conditions in order to control the brightness of the device's display screen. Light sensors often employ photodetectors such as photodiodes, phototransistors, or the like, which convert received light into an electrical signal (e.g., a current or voltage). Electronic devices can also include light sensors for communicating information. For example, devices can employ pulse oximeters, which use light to detect a person's pulse and blood oxygen levels, in order to display the person's physiological information on the display screen of the device.